The present invention relates generally to load simulators and more specifically to apparatus for applying a radially inwardly directed load on a wheel/tire assembly as the wheel/tire assembly is rotated.
Most modern day automotive assembly plants incorporate one or more wheel/tire assembly lines which operate to receive vehicle wheels and vehicle tires, mount the tires on the wheels and inflate same in preparation for mounting of the wheel/tire assemblies on the motor vehicles. Typically, these assembly lines will incorporate various items of automated equipment such as apparatus for soaping the wheel and/or tire, mounting the tire on the wheel, inflating same and finally balancing the mounted and inflated tire. The balancing apparatus incorporated in such tire lines is extremely effective in accurately balancing the wheel/tire assembly as it comes off the tire line. However, in many cases, it has been discovered that the wheel/tire assembly is out of balance after the vehicle has been driven only a very short distance. It is believed that the reason for this imbalance after a very short driving period is the fact that the tire beads do not fully seat against the rim in all cases during the mounting process. Once the vehicle has been driven even a relatively short distance with the weight of the vehicle bearing thereon, the flexing movement of the sidewall and slight warming of the tire result in complete seating of the tire bead. There are many reasons why the tire bead may not fully seat initially such as for example the fact that the tires are often somewhat distorted as received by the tire line due to the manner in which they are shipped and stored. Other factors such as a build up of tolerances or the like may result in one tire fitting relatively tightly on a particular rim and hence inhibiting the complete seating movement of the bead during the inflation process.
In any event, whatever the cause, the out of balance tires then often require warranty work to be performed either within the assembly plant prior to shipment of the vehicle to a dealer or alternatively by the dealer in order to bring the tires back into accurate balanced condition. Not only does this represent a relatively costly process in that it requires a second performance of the balancing operation, it is particularly disconcerting when the condition is discovered as a result of a customer complaint. Further, it has been noted that many wheel/tire assemblies when rebalanced require application of substantially less weight than utilized in the initial balancing in order to bring them into specification. Hence, it is exceedingly desirable to eliminate this problem both from a customer satisfaction viewpoint as well as for the labor and material cost savings which may be realized thereby.
In order to overcome these problems, the present invention has been developed which is designed to be incorporated as an additional unit within a wheel/tire assembly line and to be located between the inflator station and the balancing station. The present invention incorporates a plurality of power driven pivotable arms which are operable to move into engagement with the periphery of a mounted and inflated tire and to rotatably drive the tire up to a predetermined speed while simultaneously applying a load thereto and thereafter to decelerate the tire and advance the wheel/tire assembly into the balance station. The running up to a predetermined speed of the wheel/tire assembly while simultaneously applying a radially inwardly directed force thereon operates to effectively simulate the conditions encountered during the initial operation of the vehicle and thereby effectively seat the beads completely on the tire rim. It is believed that the use of this apparatus not only will significantly reduce the number of vehicle wheel assemblies requiring rebalancing after a short driving distance but also will achieve the additional benefit of a substantial reduction in the amount of weight which must be applied to the various wheel/tire assemblies in order to achieve the proper balancing thereof. Thus, the present invention offers substantial cost savings in eliminating or substantially reducing the amount of rebalancing required as well as reducing the cost attributable to the consumption of balancing weights.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.